I want to stream my computer with the audio being the sound comming from my computer speakers, but I don't know how to set up the audio source to do that! The programs I have downloaded are Manycam and Adobe Flash Media Live Encoder.

If you select "preferences" on procaster you can then select the "audio tab". Make sure "auto mix" is unchecked. This will allow you to see the audio feeds. Mute all choices but "speakers audio" and adjust volume accordingly. It should work...